For fish enthusiasts, keeping a sterlet in an aquarium can be a unique and fascinating experience. This species lends a touch of elegance to any aquatic setup with its graceful appearance and characteristic long snout. It’s crucial to understand that sterlets are not your typical aquarium fish, though.
A species of sturgeon that can reach fairly large sizes in the wild, the sterlet was originally found in rivers and lakes in Europe and Asia. This implies that giving your aquarium enough room is crucial to the health and happiness of your fish. Furthermore, for sterlets to flourish in a home aquarium, certain water parameters and a well-balanced diet are necessary.
It’s important to be aware of the difficulties and care needs before adding a sterlet to your tank.
| Topic | Details |
| Species | Sterlet (Acipenser ruthenus) |
| Tank Size | Minimum of 1000 liters due to the sterlet"s large size |
| Water Temperature | Cold water species; ideal range is 12-20°C |
| Diet | Feeds on sinking pellets, live food, and frozen food |
| Behavior | Peaceful, but requires a spacious environment |
Habitat in the wild
Among the oldest fish species is the sterlet. Fish have known ancestors dating back to the Silurian era. A variety of insects, invertebrates, and extinct fish with ray fins called the world home. The first vertebrate that became specialized in consuming other living things was the ancestor of the sterlet. Long before any animals set foot on land, even before the first amphibians, the ancestors of the sterlet appeared.
The rivers that flow into the Caspian, Azov, and Black Seas comprise the historical range of the sterlet. The Northern Dvina, Yenisei, and Ob are some of the chilly rivers in the North that are home to this intriguing fish. Steerlet, which is caught in the basin of Onega and Ladoga, the two largest lakes in Europe, has been prized since ancient times. There were also sterlet populations in other sizable rivers and man-made reservoirs.
Since sterlet can only survive in clean water, their population in natural reservoirs has drastically declined in recent years.
The sterlet is in danger of going extinct due to river pollution. It’s possible that this elegant and unique fish will only be found in aquariums in ten or so years.
In the wild, sterlet favors the lower basins and slopes of rivers with rocky or sandy bottoms. Adults tend to stay nearer the center of the riverbed, in areas with swift currents. Shallow water is where young individuals are found. The diet and habitat of males and females in the water column are different.
Males consume the larvae of insects such as midges, caddis flies, and amphipods. Large adult males feed primarily on leeches and mollusks. Their high activity level and preference for living in the upper water layers are the causes of this diet. The temperature of the water ranges from +6 to +29°C, and the dissolved oxygen content is -4.5–11.5%/l.
Females eat whatever is on the substrate’s surface, are sluggish, and primarily swim in the bottom layer. Numerous polychaete worms, mollusks, and some insect larvae are among their food sources. The caviar of other fish species is considered a "delicacy" by females. The sturgeon forages for food at night or in the twilight. Given how drastically different their diets are, even a gourmet can tell the difference in flavor between sturgeon and sterlet meat.
The sterlet does not migrate over great distances like its fellow sturgeons do. There are no longer any populations that moved from freshwater to the ocean. It favors a sedentary way of living. Sterlet spends the winter in small flocks in river bottom pits and pools. Without food, the fish wait out the cold by hanging motionless at the bottom.
Appearance and structural features
While sterlet and sturgeon are very similar, they are not the same. Sterlet can reach lengths of 40–60 cm and weights of 0.5–2 kg in the wild. Huge 16 kg specimens are also present. However, since the smallest fish in the entire sturgeon population, this is a rarity. It is even smaller—up to 17 cm—in an aquarium. In captivity, they develop slowly.
The body of the sterlet is spindle-shaped and elongated, with five rows of tough bony scutes, or "bugs." The absence of an internal bone skeleton is made up for by these shields. The basic components of the vertebral arches are represented by a cartilaginous chord in the sterlet spine. Furthermore cartilaginous are the ribs. The skeleton’s structure suggests the fish’s ancient ancestry.
An expert fisherman or ichthyologist can tell sterlet from sturgeon by counting the "bugs." There are 10–15 fewer bone plates in sterlet (57–71). There are three rows on the body: two on the sides, two on the ventral side, and one on the back. There are sharp conical shields in between the bugs.
The head is small compared to the body, elongated, and ends in a long, pointed snout called the rostrum. Younger people have a sharper rostrum. The sterlet’s head becomes rounder and wider in the front as it ages. The outside of the skull is covered in bony scutes.
The lower mouth is symbolized by a thin, horizontal slit. Teeth are absent; only sterlet larvae have teeth. There is a division in the lower lip. The oral funnel expands when consuming food from the bottom; this feature aids in "sucking" microscopic organisms from the bottom.
The fish cannot see food on the bottom because its eyes are situated above its mouth. Two pairs of sensitive fringed barbels, situated in front of the mouth opening, aid in the detection of larvae. Taste buds are found here, so with their assistance the fish not only locates an object but also decides if it is fit for consumption. There are spiracles on the upper surface of the rostrum, nasal openings on both sides of the axial line, and spiracles behind the eyes at the top of the gill cover.
Overlying the upper portion of the caudal trunk is a point formed by three layers of ossified shields, or ganoid scales. It only has the fin attached to the lower portion. Because of its heterocercal form, which has a smaller lower "lobe" than an upper one, the fish is able to stay close to the bottom without touching it with its caudal fin. The two fins are positioned horizontally in relation to the body. The sterlet’s structure combines elements of bony fish and ancient cartilaginous ganoids.
The habitat has an impact on the body’s color. The belly is light yellowish-white, and the back is dark grayish-brown. The fins are gray, and the "bugs" are a dirty gray color. Aquaristics is a popular hobby for albino sterlets. Fish farming also values this form. Albinos yield white caviare, as opposed to the typical sterlet, which produces black. A jar containing 250 grams of the highly prized "white pearl" or "golden caviar" costs $1,225.
Home aquarium equipment
While sterlet is not particularly fussy about its diet, it is highly attuned to the properties and purity of its water. Cute royal sturgeon relatives are therefore not for the faint of heart. The water needs to be crystal clear in order to replicate the natural habitat. The aquarium needs to have a strong filtration and aeration system in order to do this. Four to six volumes per hour should be the minimum filter capacity.
Although a flow-through aquarium is ideal, there are several reasons that complicate how the "flow" is organized:
- need for large areas;
- inflow of water of a certain hardness, acidity, without chlorine and other toxic substances;
- equipment of its own water supply and drainage.
Thus, there is only one option for a home aquarium: a sizable container with an effective aeration and cleaning system. A water heater is not necessary in the middle zone because the typical sterlet temperature ranges from +6 to +25 °C. However, since sterlet cannot withstand abrupt temperature changes, knowledgeable aquarium keepers install a device that guards against overheating in species aquariums containing sturgeons.
Moreover, the following environmental parameters ought to be noted:
- pH = 6.5-8.5 pH;
- total hardness 6-25 dGH.
Weekly replacement of up to 25–30% of the water volume is required. Mucus from the sterlet’s body coats its body and contaminates the water. It makes sense to implement a biological and mechanical filtration system. The pump ought to mimic the river’s flow.
A layer of smooth-surfaced river sand, pebbles, or gravel covers the bottom. The sterlet becomes vulnerable in plant thickets or stone piles due to the presence of "bugs." You should fill the space with plants instead of using soil decoration in a species aquarium. Planting one or two bushes will suffice.
- Vallisneria americana – bushes with narrow erect leaves;
- Elodea canadensis – with pinnate delicate leaves;
- Podgeweed shining.
These are the kinds of plants that enjoy cool running water. Expert aquarium keepers advise against using even this minimal since mature sterlets will just "sweep away" uncommon bushes. Sturgeon require open water with plenty of room to swim and no shelter.
A sterlet needs a large aquarium, with at least 500 liters for each individual. Fish of the same size get along well with sturgeons, but you should choose species that thrive in colder waters, such as:
Certain aquarists have succeeded in "making friends" with tropical and sterlet fish.
Nutrition and feeding regime
Steerlet consume living things. The aquarium’s predators are still eating what they usually eat. They consume frozen and live food:
- tubifex;
- bloodworms;
- gnat larvae;
- mollusks;
- small unarmored shrimp.
Long-time aquarium owners who have kept sterlet sharks will attest to the gluttony of these small sharks. Sterlet is a voracious eater, especially after dark.
The fish are fed two or three times a day because they cannot starve.
Initially, compound feed was the norm for those imported from fish farms. They enjoy eating sturgeon food as a result.
Also read:
- aquarium piranhas;
- snakeheads in an aquarium;
- dwarf tetraodon.
Maintaining a sterlet in an aquarium can be an interesting experience, but it calls for careful preparation and a dedication to creating the ideal habitat. To survive and thrive, these freshwater sturgeon species require large tanks with high-quality water, appropriate filtration, and a temperature that is regularly monitored. Sterlets can add a dramatic touch to your aquarium, but because of their special care needs and large space requirements, they are best suited for seasoned aquarium owners.
Features of development and reproduction
Male sterlet reaches sexual maturity at the age of 3–10 years, while female sterlet reaches sexual maturity 1-2 years later. In artificial environments, abundant food and warm water speed up sexual maturation. Older females can spawn once every few years, while younger females can do so up to twice a year.
Although sterlet sexual dimorphism is not very evident, males during the spawning season grow a white coating on their heads known as the "mating dress." Occasionally, "pearl dust" coats the fish’s body. It is less obvious in females, but their bellies round out.
Up to 16,000 dark eggs can be laid by a single female.
They are all spawned simultaneously by the female, and the spawning process can take several hours.
The water flow purges the eggs of impurities while the sticky eggs are securely adhered to the stones. The eggs hatch into larvae after a few days. Six days may pass during the incubation period at low temperatures (+15–17 °C). The yolk sac’s reserves carry out feeding; the digestive tract is sealed and packed with nutrient-rich granules.
The esophagus and intestines join after 8–9 days, and the digestive system is prepared for exogenous nutrition when the melanin plug emerges from the anus after an additional 1–2 days. The fry can be fed finely chopped tubifex on the tenth day. The fry is 1.5 cm in size.
Sterlet can hybridize with other sturgeon species, such as kaluga, beluga, thorn, and stellate sturgeon, both naturally and through artificial breeding. Reproduction is nearly impossible to accomplish in an aquarium. Without cooling and hormonal stimulation, the female will not be able to spawn eggs even if she "gains" them.
Cold-water fish aquariums and open-air backyard ponds are growing in popularity these days. The sterlet will shine in them as the most venerable, exquisite, and enigmatic fish.
Photo of sterlet
Although it takes commitment and careful planning, keeping a sterlet in an aquarium can be a rewarding experience. Because of their unusual requirements and ancient ancestry, these fish stand out in any aquarium setup. However, only committed aquarists should try to care for them due to their size and sensitivity to water quality.
With enough room, fresh water, and a suitable diet, you can watch this amazing animal flourish. Since sterlets aren’t like other aquarium fish, the care you give them will show in their development and well-being.
Whether you find their ancient appearance fascinating or you like the challenge of maintaining a larger, more demanding
